1. Field of the Invention
The present invention relates to electrical connectors, and more particularly to a land grid array (LGA) socket for electrically connecting a land grid array (LGA) package to a printed circuit board (PCB).
2. Description of Related Art
An integrated circuit (IC) package having contact pads arranged on a bottom surface thereof in a land grid array (LGA) is known as an LGA package. LGA packages have relatively low height, which saves valuable space in electronic assemblies.
Connectors for removably mounting an LGA package on a PCB are known as LGA sockets. An LGA socket assembly typically comprises an insulative housing, which is positioned between the LGA package and the PCB. The housing defines an array of passageways receiving electrical contacts therein. The contacts correspond with the array of contact pads of the LGA package. Each contact has a pair of opposite free ends that project beyond opposite external surfaces of the housing. Prior to mounting of the LGA package, the free ends are spaced apart a predetermined distance. The free ends are respectively engaged with corresponding contact pads of the LGA package, and soldered to contact pads on a mounting surface of the PCB. The LGA package is positioned on the housing, and the contact pads of the LGA package rest on the contacts of the housing. Thereupon, it is necessary to exert a force upon the LGA package to maintain firm electrical connection between the contacts pads of the LGA package and the respective contacts of the housing. The force is powerful enough to maintain the electrical connection between the contacts pads and the contacts.
Various LGA sockets comprising a cover slidably mounted on the housing to provide the force are disclosed in, for example, U.S. Pat. Nos. 4,504,105, 4,621,884, 4,692,790, 5,302,853, and 5,344,334. Referring to FIG. 1, a typical such LGA socket 9 comprises a cover 93 and a metallic lever 92 respectively mounted to opposite ends of a housing 91. The end of the housing 91 mounted with the cover 93 defines a pair of troughs mating with a pair of corresponding hooks extending from an end of the cover 93. The opposite end of the housing 91 forms a pair of braces holding the lever 92. A pair of protuberances 911 is respectively defined on the surfaces of the braces, the protuberances 911 holding the lever 92 in a horizontal position.
The housing 91 and the protuberances 911 are made of plastic, and the protuberances 911 wear out after repeated use of the lever 92. When the protuberances 911 have become too small, they can no longer reliably retain the lever 92. Opposite lateral sides of the cover 93 are bent slightly downwardly to form a pair of clasping portions. When the LGA socket 9 is not in use, the cover 93 is rotated down onto the housing 91, and the clasping portions rest on a top surface of the housing 91.
In use, an LGA package 8 is positioned on the housing 91. The cover 93 is rotated down onto the LGA package 8, with the clasping portions resting on the LGA package 8. The lever 92 is rotated down, and engages with a free end of the cover 93. The lever 92 thus presses the clasping portions of the cover 93 onto the LGA package 8.
Because the lever 92 presses down on the cover 93, and the clasping portions of the cover 93 press down on the LGA package 8, the lever 92 simultaneously pulls up the end of the housing 91 thereat to counterbalance the pressing forces. In addition, the hooks of the cover 93 tend to pull up the end of the housing 91 thereat, to counterbalance the pressing forces of the clasping portions of the cover 93.
Generally, the force required for the clasping portions of the cover 93 to firmly retain the LGA package 8 thereunder is considerable. Accordingly, the pressing force applied by the lever 92 on the cover 93 is also considerable. The result is that the pulling up force of the lever 92 is considerable, and the pulling up force of the cover 93 is also considerable.
Said pulling up forces operate on the opposite ends of the housing 91 respectively, and the pressing forces of the clasping portions of the cover 93 operate to press a center portion of the housing 91 downward. Because the housing 91 is made of plastic, it has limited rigidity. As a result, the opposite ends of the housing 91 tend to bend upward. The forces applied by the clasping portions of the cover 93 on the LGA package 8 are decreased. The upshot is that firm and reliable electrical connection between the contacts pads of the LGA package 8 and the contacts of the housing 91 is diminished.
It is therefore an object of the present invention to provide an LGA socket for electrically connecting a land grid array (LGA) package to a printed circuit board (PCB), wherein contacts pads of the LGA package can be firmly and reliably connected with respective contacts of the LGA socket.
To achieve the above object, an LGA socket assembly of the present invention is provided for electrically connecting a land grid array (LGA) package to a printed circuit board (PCB) The LGA socket comprises a slab like insulative housing, a reinforcing plate attached on an exterior surface of the housing, and a clip and a lever. The clip and the lever are respectively mounted on two opposite ends of the housing to fasten an LGA package. The lever includes a driver portion, a driven portion adjoining the driver portion, and a baffle extending from a side of the reinforcing plate. The baffle prevents the lever from breaking away from the housing. After the LGA package is positioned on the housing, the rigidity of the housing is improved with the reinforcing plate made of rigid material being equipped on the housing. Steady electrical connection between the contacts pads of the LGA package and respective contacts of the housing is ensured.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.